In this article we will
create a registration page with captcha implemented to it.
Before going forward we
should know what is captcha?
CAPTCHA:
- Completely Automated Public Turing test to tell
Computers and Humans Apart. A captcha is a program that
protects websites against bots by generating and grading tests that humans can
pass but current computer programs cannot. For example, humans can read
distorted text but current computer programs can't.
Characteristics: A captcha is
a means of automatically generating challenges which intends to:
- Provide a problem easy
enough for all humans to solve.
- Prevent standard automated software
from filling out a form, unless it is specially designed to circumvent specific
CAPTCHA systems.
For more information please visit
http://www.captcha.net
http://en.wikipedia.org/wiki/CAPTCHA
Table structure
Create two tables employee
and country as below:
Program
Default.aspx code
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Registration
Page</title>
<style type="text/css">
#datePicker
{
display:none;
position:absolute;
border:solid 2px black;
background-color:white;
}
.content
{
width:400px;
background-color:white;
margin:auto;
padding:10px;
}
html
{
background-color:white;
}
.style10
{
background-color: #eeeeee;
height: 26px;
}
.style11
{
height: 26px;
}
.style12
{
background-color: #eeeeee;
}
</style>
<link href="style.css" rel="stylesheet" type="text/css" />
</head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td class="deepbluetextbold"><b>Employee
Information</b></td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel1" AssociatedControlID="LocationLabel1" CssClass="style7" Text="Title" />
</td>
<td>
<asp:RadioButtonList id="rb1" runat="server" RepeatLayout="Flow" RepeatColumns="4"
RepeatDirection="Horizontal" Width="200px" >
<asp:ListItem Text="Mr."
Selected="False"/>
<asp:ListItem Text="Mrs."/>
<asp:ListItem Text="M/S"/>
<asp:ListItem Text="Dr."/>
</asp:RadioButtonList>
</td>
<td><asp:RequiredFieldValidator ID="rfv1" Text="Select any Choice" runat="server"
ControlToValidate="rb1"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel2" AssociatedControlID="LocationLabel2" CssClass="style7" Text="Name*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtname" Width="200px" />
</td>
<td>
<asp:RequiredFieldValidator ID="rfv2" Text="Please Enter the
Name" runat="server" ControlToValidate="txtname"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel3" AssociatedControlID="LocationLabel3" CssClass="style7" Text="Email*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtemail" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv3" Text="Please Enter the
Email" runat="server" ControlToValidate="txtemail"></asp:RequiredFieldValidator>
</td>
<td> <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server"
ErrorMessage="Please
enter valid email"
ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"
ControlToValidate="txtemail"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel4" AssociatedControlID="LocationLabel4" CssClass="style7" Text="Date of Birth*" />
</td>
<td colspan="0" rowspan="1">
<asp:TextBox runat="server" ID="txtdateofbirth" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv4" Text="Please Enter the
Dateofbirth" runat="server" ControlToValidate="txtdateofbirth"
</asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel5" AssociatedControlID="LocationLabel5" CssClass="style7" Text="Guest?*" />
</td>
<td>
<asp:RadioButtonList id="rb2" runat="server" RepeatLayout="Flow" RepeatColumns="3" RepeatDirection="Horizontal" >
<asp:ListItem Text="Yes"
Selected="False"/>
<asp:ListItem Text="No"/>
</asp:RadioButtonList>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv5" Text="Select yes or no" runat="server" ControlToValidate="rb2"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel6" AssociatedControlID="LocationLabel6"
CssClass="style7" Text="Company/Organization*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtcompany" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv6" Text="Please Enter the
Company" runat="server" ControlToValidate="txtcompany"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel7" AssociatedControlID="LocationLabel7"
CssClass="style7" Text="Designation*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtdeg" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv7" Text="Please Enter the
Designation" runat="server" ControlToValidate="txtdeg"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel8" AssociatedControlID="LocationLabel8"
CssClass="style7" Text="Street Address*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtaddress" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv8" Text="Please Enter the
Street Address" runat="server" ControlToValidate="txtaddress"
</asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel9" AssociatedControlID="LocationLabel9"
CssClass="style7" Text="City*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtcity" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv9" Text="Please Enter the
Street City" runat="server" ControlToValidate="txtcity"</asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel10" AssociatedControlID="LocationLabel10"
CssClass="style7" Text="State" />
</td>
<td>
<asp:TextBox runat="server" ID="txtstate" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv10" Text="Please Enter the
Street state" runat="server" ControlToValidate="txtstate"
</asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel11" AssociatedControlID="LocationLabel11"
CssClass="style7" Text="Zip Code*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtzip" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv11" Text="Please Enter the
Zip" runat="server" ControlToValidate="txtzip"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="style10">
<asp:Label runat="server" ID="LocationLabel12" AssociatedControlID="LocationLabel12"
CssClass="style7" Text="Phone*" />
</td>
<td class="style11">
<asp:TextBox runat="server" ID="txtphone" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv12" Text="Please Enter the
Phone" runat="server" ControlToValidate="txtphone
</asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel13" AssociatedControlID="LocationLabel13"
CssClass="style7" Text="Fax*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtfax" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv13" Text="Please Enter the
Fax" runat="server" ControlToValidate="txtfax"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel14" AssociatedControlID="LocationLabel14"
CssClass="style7" Text="Website*" />
</td>
<td>
<asp:TextBox runat="server" ID="txtwebsite" Width="200px"/>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv14" Text="Please Enter the
Website" runat="server" ControlToValidate="txtwebsite"</asp:RequiredFieldValidator>
</td>
<td> <asp:RegularExpressionValidator ID="RegularExpressionValidator2" runat="server"
ErrorMessage="Please
enter valid Url"
ValidationExpression="http(s)?://([\w-]+\.)+[\w-]+(/[\w-
./?%&=]*)?"
ControlToValidate="txtwebsite"></asp:RegularExpressionValidator>
</td>
</tr>
<tr>
<td class="style12">
<asp:Label runat="server" ID="LocationLabel15" AssociatedControlID="LocationLabel15"
CssClass="style7" Text="Country*" />
</td>
<td>
<asp:DropDownList ID="d1" Width="200px" runat="server">
<asp:ListItem>Select</asp:ListItem>
</asp:DropDownList>
</td>
<td>
<asp:RequiredFieldValidator ID="rfv15" Text="Please select any
value" runat="server" ControlToValidate="d1"></asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td class="colouredCell">
<asp:Label runat="server" ID="LocationLabel16" AssociatedControlID="LocationLabel16"
CssClass="style7" Text="Captcha Image*" />
</td>
<td><asp:TextBox runat="server" ID="txtcaptcha" Width="200px"/></td>
<td>
<img style="WIDTH:
119px; HEIGHT:
34px" alt="" src="Captcha.aspx" />
</td>
<td><a href="Default.aspx" id="uu">Can't
Read?</a></td>
</tr>
</table>
</div>
<asp:Button ID="b1" runat="server" Text="Register" />
</form>
</body>
</html>
Default.aspx.vb code
Imports
System.Data
Imports
System.Data.SqlClient
Partial Class _Default
Inherits System.Web.UI.Page
Dim strConnString As String =
System.Configuration.ConfigurationManager.ConnectionStrings.Item("ConnectionString").ToString()
Dim sqlda As
SqlDataAdapter
Dim com As
SqlCommand
Dim ds As
DataSet
Dim
dt As DataTable
Dim str As String
Dim con As New SqlConnection(strConnString)
Protected Sub
Page_Load(ByVal sender
As Object, ByVal
e As System.EventArgs)
Handles Me.Load
If Not
Page.IsPostBack Then
con.Open()
str =
"select * from country"
com =
New SqlCommand(str, con)
Dim reader As
SqlDataReader = com.ExecuteReader
While reader.Read
d1.Items.Add(reader("countryname"))
End While
reader.Close()
con.Close()
End If
End Sub
Protected Sub
b1_Click(ByVal sender
As Object, ByVal
e As System.EventArgs)
Handles b1.Click
Try
con.Open()
If Session("randomStr").ToString()
= txtcaptcha.Text Then
str =
"insert into employee values ('" &
rb1.SelectedValue & "','" & txtname.Text &
"','" & txtemail.Text &
"','" & txtdateofbirth.Text &
"','" & rb2.SelectedValue &
"','" & txtcompany.Text &
"','" & txtdeg.Text &
"','" & txtaddress.Text &
"','" & txtcity.Text &
"','" & txtstate.Text &
"','" & txtzip.Text &
"'," & txtphone.Text &
"," & txtfax.Text &
",'" & txtwebsite.Text &
"','" & d1.SelectedValue &
"','" & txtcaptcha.Text &
"')"
com =
New SqlCommand(str, con)
com.ExecuteNonQuery()
Response.Redirect("Success.aspx")
con.Close()
Else
Response.Write("Wrong text inserted ,Please enter
new characters shown in image textbox")
End If
Catch err As
Exception
Response.Write(err.Message)
End Try
End Sub
End Class
Captcha.aspx code
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Captcha.aspx.vb" Inherits="Captcha" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled
Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
</form>
</body>
</html>
Captcha.aspx.vb code
Imports
System.Drawing
Imports
System.Drawing.Imaging
Imports
System.Drawing.Text
Partial Class Captcha
Inherits System.Web.UI.Page
Protected Sub
Page_Load(ByVal sender
As Object, ByVal
e As System.EventArgs)
Handles Me.Load
'create object of Bitmap Class and set its width and
height.
Dim objBMP As
Bitmap = New Bitmap(180, 51)
'Create Graphics object and assign bitmap object to
graphics' object.
Dim objGraphics As
Graphics = Graphics.FromImage(objBMP)
objGraphics.Clear(Color.OrangeRed)
objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias
Dim objFont As
Font = New Font("arial",
30, FontStyle.Regular)
'genetating random 6 digit random number
Dim randomStr As String = GeneratePassword()
'set this random number in session
Session.Add("randomStr",
randomStr)
objGraphics.DrawString(randomStr, objFont, Brushes.White, 2, 2)
Response.ContentType = "image/GIF"
objBMP.Save(Response.OutputStream, ImageFormat.Gif)
objFont.Dispose()
objGraphics.Dispose()
objBMP.Dispose()
End Sub
Public Function
GeneratePassword() As
String
' Below code describes how to create random
numbers.some of the digits and letters
' are ommited because they look same like "i","o","1","0","I","O".
Dim allowedChars As String = "a,b,c,d,e,f,g,h,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,"
allowedChars +=
"A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z,"
allowedChars +=
"2,3,4,5,6,7,8,9"
Dim sep() As Char = {","c}
Dim arr() As String = allowedChars.Split(sep)
Dim passwordString As String = ""
Dim temp As String
Dim
rand As Random = New
Random()
Dim i As Integer
For i = 0 To 6 -
1 Step i + 1
temp =
arr(rand.Next(0, arr.Length))
passwordString
+= temp
Next
Return passwordString
End Function
End Class
Output
Thanks for reading